SLIP-39
Shamir backup · Shamir's secret sharing
SLIP-39 is a standard for splitting a wallet's master secret into word shares, so that a chosen number of shares rebuilds it and fewer reveal nothing useful.
Each share is 20 words for a 128-bit secret or 33 words for a 256-bit one, drawn from a list of 1024 words. Shares can be organised in up to 16 groups with up to 16 members each, each with its own threshold.
Three checksum words at the end of every share detect any error affecting up to three words. The specification advises against automatic correction of errors, which could silently produce a different valid secret.
SLIP-39 is not compatible with BIP39: a share cannot be restored in a BIP39-only wallet. See what is a Shamir backup.
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